This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The goal of this subproject is to characterize the proteome of embryonic mouse stem cell development. This work also includes sub-cellular fractionation of the proteome to identify protein groups of particular interest.